Solar Photovoltaics Contribution To Energy Mix In Selected Nigerian Estates

This paper assessed the share of Solar Photovoltaics (PV) in the energy mix for various energy services in Nigerian residential estate. Model for Analysis of Energy Demand (MADE-II) was used to analyze the primary and other secondary data obtained for the study. The results showed that the current contribution of solar PV in energy demand split for the estates was still low, with a total share of 8.8%, 6.7% and 4.4% in Ijapo, Alagbaka and Sunshine Housing Estate despite various government interventions. Its usage level constituted an insignificant share of 27.9%, 57.3%, 18.3%, 0%, 0%, 0%, 0%, and 16.8% for the total lighting, computing/internet, entertainment, process heat, cooking, refrigeration, water pumping and ventilation services requirement respectively in Ijapo Housing Estate, 26.5%, 70.6%, 13.7%, 0%, 0%, 0%, 0%, and 16.5% in Alagbaka Housing Estate, and 24.0%, 50%, 14.1%, 0%, 0%, 0%, 0%, and 1.8% in Sunshine Housing Estate. The study concluded that utilization of solar PV as an energy source for energy service ensure access to affordable, reliable, sustainable and modern energy for all. The research recommended that government support for solar PV intervention should be further encouraged.


INTRODUCTION
Globally, the utilization of Solar Photovoltaic (PV) among residential is attracting more researchers' interests in the recent times. This was influenced by a call to action made in 2015 at the United Nations Summit for Sustainable Development for a much wider and greater access to affordable, reliable and sustainable energy as a prerequisite for eradicating poverty by 2030 [1]. World leaders affirm this in 2016 at their summit with a global consensus that: the Sustainable Development Goals (SDGs) is not achievable without efficient energy access to increase production, income, create jobs and reduce drudgery [2]. The importance of access to energy in facilitating economic development, reducing poverty, broadening the reach of education and improving health has been well explored [3, 4, 5, & 6]. electricity. These surfaces have no moving parts to wear out or suffer breakdowns and works without the use of fuel without vibrations without noise and without harming the environment. It is responsible for trapping of solar energy as it is placed outside under the sun. They are arranged in series and parallel to meet desired output [16, 17 & 18].

Charge Controller
A charge controller monitors the battery's state-of-charge to insure that when the battery needs charge current, it gets it and also ensures the battery isn't overcharged. Connecting a solar panel to a battery without a regulator seriously risks damaging the battery and potentially causing a safety concern [16, 17 & 18].

Inverter
Required to convert the direct current (DC) power produced by the PV module into Alternating current (AC) power. Most solar power systems generate Dc current which is stored in batteries while nearly all lighting, appliances, motors and so on, are designed to use AC power, so it takes an inverter to make the switch from battery-stored DC to standard power (120VAC, 60Hz) [16, 17 & 18].

Deep Cycle Battery:
It stores electricity to provide energy on demand at night or on overcast days. They are designed to be discharged and then recharged hundreds or thousands of times. These batteries are rated in amp-hours, usually at 20 hours and 100 hours. Like solar panels, batteries are wired in series and/or parallel to increase the voltage to the desired level and increase amp hours. The recommended batteries that should be used in a stand-alone photovoltaic power system are deep-cycle lead-acid batteries because of their high performance [16, 17 & 18]. Empirical Literature On Solar Pv Contribution To Energy Service Solar Photovoltaic market is a rapidly growing worldwide [19]. During the period between 2000 and 2015 the growth rate of photovoltaic installations was of 41%. It is observed that China and Taiwan since 2006 have been increasing the photovoltaic industry with strong growth rates. At the end of 2015, its market share was about 71% of global sales. The market for photovoltaic systems will likely continue to grow in the future as strongly as so far, due to the thrust of subsidies, tax breaks and other financial incentives. Support for R & D and photovoltaic technology change are crucial aspects in accelerating the widespread utilization of photovoltaic systems [19].
Europe contributed 40% of total cumulative PV installations in 2015 (in 2014 it was 48%). European countries such as Germany, Denmark and Spain, in addition to Asian countries China and Taiwan, have used feed-in tariff (FIT) which is a political mechanism to encourage consumers to invest in renewable microgeneration. On the other hand, the United States, United Kingdom, Japan and Sweden, have used the RPS (Renewable Portfolio Standard), which is a regulation that requires that part of the energy consumed comes from renewable sources.
The facilities in China and Taiwan accounted for 21% of total cumulative installations (in 2014 was 17%). In 2015, Germany accounted for about 16% (39.6 GWp) of cumulative installed PV capacity worldwide (242 GWp). In 2015, the newly installed capacity in Germany was about 1.4 GWP; in 2014 it was 1.9 GWp. In total, 1.5 million photovoltaic systems were installed in Germany. Jesuleye (2017) [20] analyzed the current status of Solar Photovoltaics (PV) for lighting in Danjiwa and Dahuwa remote villages that are pilot sites for rural electrification projects in Nigeria. Model for Analysis of Energy Demand (MADE-II) was used to analyze the primary and other secondary data obtained for the study. The results showed that the current contribution of solar PV in the lighting demand split for the villages was still very low in spite of various government interventions. Its usage level constituted an insignificant share of 16.4% and 5.5% of the total lighting requirement for Danjiwa and Dahuwa villages respectively. For each village, lighting with incandescent bulbs was about 10% of this total requirement, while that of fluorescent lambs stood at 7% and 6.5 respectively. The research results also revealed that kerosene maintained a domineering share of 66% and 77% of the total demand in the two villages respectively.
Ismail, Ajide and Akingbesote (2012) [21], embarked on performance assessment of installed solar PV system in Oke agunla, Akure LG area of Ondo state in Nigeria, it was concluded that the PV systems were inefficient as a result of poor maintenance, lack of technical know-how and inability of the project contractors or managers to take these factors into consideration while embarking on the solar PV installations. Melodi & Famakin (2011) [22], in a study to determine the adequacy of solar electricity potential (SEP) for meeting the domestic demand of Akure, concluded that SEP in Akure is appreciable and sufficient as an alternative energy source for domestic needs.

METHODOLOGY OF THE STUDY Adaptation of Model for Analysis of Demand for Energy (MADE-II) for Data Analysis
Model for Analysis of Demand Energy (with the acronyms MADE-II), developed at the Institute for Energy Economics and Rational use of Energy, University of Stuttgart, Germany in 1989, is the adapted energy demand analysis model for this paper. The Model combines the application of statistical, econometric and engineering process techniques as appropriate for the various sectors of the economy. As presented in Figure. 2. MADE-II is made up of 7 blocks of data in flow for demand analysis. Block 1 deals with general information about energy levels, base year and future time periods while information on development of population is presented in Block 2. Data analysis for useful energy demand in the households sector is treated in Block 3, while block 4 and 5 deal with the Households, Cottage Industries and Community Services sectors. The transport sector is not included in the analysis while block 7 deals with efficiencies, penetration factors and sectoral demand for Solar Electricity Lighting. Other Energy Services such as: Water Pumping for Drinking and Irrigation Purposes, Powering of TV, Video, Radio, Refrigeration, Ventilation, Cooking and Process Heat are not considered in the analysis due to dearth of data.
The basic analytical approach employed in MADE-II which makes it suitable for demand analysis of solar electricity in Nigeria is its flexibility and applicability for demand projection over short or long period. So also, analytical techniques adopted in MADE-II rest on the idea that energy is a means to an end and it is used together with other production factors to provide products (in form of goods and services) to the society.

Measurement of Variables for energy services by Solar PV in Each Estate
Energy consumption data of each village in the study areas were used to quantify total demand for energy services. This involves the calculation of energy intensities as represented in the equation as below: Energy Intensity (EIj,t) = ((DSESj,t)Energy input (Wp))/((AL j,t)Population Share (Million)) Where, DSESj.t = ALj,t * EIj,t DSESj,t : Household demand D for Solar PV Services j (e.g. lighting ) in time t. Alagbaka Housing Estate is also located in the peripheral zone of the city near the Bishop's Court roundabout. It is a site-and-services estate where the residents purchased the land from the government in order to build by themselves while the government provides the services. With a population of 1540, Table 2 shows a Profile of Solar PV installation in the study area. In Alagbaka Housing Estate, the number of household Connected is 59, which makes 19.2% of the households Estate. The most common application is solar home system installation with a Total capacity of 93KW which were installed between 2013 and 2018. The installation comprises of Solar Panel, Storage Battery, Inverter, Charge controllers and ELCB Breaker. The PV Installation is used as an alternative Energy source. The PV installations are Self-sponsored, and 54.2% of the respondents stated that the PV system is working very well and last an average of 5-6 hours. The users are responsible for monitoring and sustainability. Sunshine Housing Estate is located in a suburb of the Akure city called Oba-Ile. It is a prototype-housing estate built through Public-Private Partnership between the State government and a private developer, who built all the houses and provided the services, while the users purchased the already finished houses. With a population of 880, Table 3 presents a Profile of Solar PV installation in the study area. In Sunshine Gate Housing Estate, the number of household Connected is 32, which makes 18.2% of the households in the Estate. The most common application is solar home system installation with a Total capacity of 39.5KW which were installed between 2012 and 2018. The installation comprises of Solar Panel, Storage Battery, Inverter, Charge controllers and ELCB Breaker. The PV Installation is used as an alternative Energy source. The PV installations are Self-sponsored, and 87.5% of the respondents Stated that the PV system is working very well and last an average of 5-6 hours. The users are responsible for monitoring and sustainability.

Data presentation and Analysis
This chapter presents the statistical analysis results and discussion on the assessment of Solar Photovoltaic Utilization for energy services in selected estates in Akure, Ondo State. The response rate of the survey questionnaire collected was examined in line with the study of Cooper and Schindler (2007)[24], who explained that the collected raw data should be examined for correctness, accuracy and completeness. In this study, 300 copies of questionnaire were administered to respondents. 165 questionnaires were administered in Ijapo Housing Estate, and 128 were completed correctly and returned, representing a percentage response of 78%. 85 was distributed in Alagbaka Housing Estate, and 59 were completed correctly and returned representing a percentage response of 69% while 50 was shared in Sunshine Housing Estate, and 32 were completed correctly and returned representing a percentage response of 64%. A total of 219 were completed correctly and returned, representing a percentage response of 73%, as shown in Table 4. Mugenda and Mugenda (2003)[25], states that a response rate of 50% is adequate for analysis and reporting; a rate of 60% is good, and a response rate of 70% and over is Excellent. Hence the response rate was satisfactory, as indicated in Table 4.

Demographic Information of Respondents
This section discussed the demographic information of the respondents in Ijapo Housing Estate. First, the researcher sought to establish the gender of the respondents. Their responses are shown in Table 4. In Ijapo Housing Estate (IHE), 84.4% of the respondents are males, while 15.6% are female. In Alagbaka Housing Estate (AHE), 81.4% of the respondents are males, while 18.6% are female. In Sunshine Housing Estate (SHE), all the respondents are males. Overall 85.8% of the household heads were males while as 14.2% of the household heads were females. This implies that there were more male respondents than females. This may be so because of the dominance of male as head of household in Africa [26]. This, however, will not affect the responses from the respondents, thereby creating any form of biasness. Next, sought to establish the age of the household heads. Their responses are highlighted in Table 5. In Ijapo Housing Estate (IHE), None (0%) of the respondents were aged below 20 years, 10.9% of the household heads were aged between 21 to 29 years, 48.4% of the household heads were aged between 31 to 39 years and 40.6% of the household heads were aged 40 years and above. In Alagbaka Housing Estate (AHE), None (0%) of the respondents were aged below 20 years, and between 21 to 29 years, 76.3% of the household heads were aged between 31 to 39 years, and 23.7% of the household heads were aged 40 years and above. In Sunshine Housing Estate (SHE), None (0%) of the respondents were aged below 20 years, and between 21 to 29 years, 57.5% of the household heads were aged between 31 to 39 years, and 36.1% of the household heads were aged 40 years and above. Overall None (0%) of the respondents were aged below 20 years, 6.4% of the household heads were aged between 21 to 29 years, 57.5% of the household heads were aged between 31 to 39 years, and 36.1% of the household heads were aged 40 years and above. This shows that the largest population of respondents were young and matured enough; as a result, they were able to understand issues related to solar technology. Table 5 also reflect a compliment to their level of education as the study composition indicates clearly that in Ijapo Housing Estate (IHE), 71.1% of the respondents have already earned a bachelor degree, while 6.3%, 21.9% and 0.8% are holders of HND, Masters and PhD Respectively. In Alagbaka Housing Estate (AHE), 86.4% of the respondents have already earned a bachelor degree, while 5.1% and 8.5% are holders of HND, Masters Respectively and none (0%) are OND/Certificate and PhD holder. In Sunshine Housing Estate (SHE), 71.9.4% of the respondents have already earned a bachelor degree, while 3.1% and 25% are holders of HND, Masters Respectively and none (0%) are OND/Certificate and PhD holder. Overall, 75.3% of the respondents have already earned a bachelor degree, while 5.5%, 18.7%, and 0.5% are holders of HND, Masters and PhD Respectively. This might be an implication that they are well informed, and possessed the ability to assess and process information (tangible and intangible benefit accrue to the use of Solar PV) toward making a decision in line with the utilization of a Solar PV.

Share of Solar PV in the energy mix for energy services in the study area
Calculation of energy intensity is essential to determine the demand for various energy services in the study areas. Variables such as technical efficiency of various end-use appliances (usually referred to as the end-use appliances power ratings in kilowatts), stock and duration  Table 9.     Table 4.6 also shows the total daily per household energy demand for laptops and desktop computer as 0.32Kwh, Power stabilizer is 0.83Kwh, phone and tablet is 0.13Kwh, and the Game console is 0.05Kwh. The overall daily per household energy demand for Computing and Internet Services is 1.33Kwh. The total daily per household energy demand for entertainment stood at 1.36 Kwh/HH/day, which includes radio, TV, video and musical instruments. The total daily per household energy demand for appliances for Process heat stood at 0.69 Kwh/HH/day which includes shaving kits, washing machine (0.19Kwh/HH/day), blender (0.14Kwh/HH/day) and Iron (0.36Kwh/HH/day). Table 12 further reveals the total daily per household energy demand for appliances for cooking services is 4.85Kwh/HH/day, which is used by the electric cooker.
Other means of cooking includes firewood stove, kerosene stove and improved firewood stove but are not in use in the estates. However, the Gas cooker is commonly used for cooking in the estate with an average number of the appliance of 1. The total daily per household energy demand for water pumping for drinking is 0.29Kwh/HH/day. The total daily household energy demand for refrigeration services have the highest daily per household energy use of 11.5Kwh/HH/day. The total daily per household energy demand for appliances for Ventilation services is 6.05Kwh/HH/day. The Total daily per household for all energy services is 28.49 Kwh/HH/day, as shown in Table 12.             Table 17 shows that in Ijapo Housing Estate, share of PV in Lighting services is 27.9%, Computing/internet services is 57.3%, Entertainment Services is 18.3%, Process heat Services is 0%, Cooking Services is 0%, Water pumping Services is 0%, Refrigeration services is 0%, and Ventilation services is 16.8%. The Total share of PV for energy services in Ijapo Housing Estate is 8.8%. In Alagbaka Housing Estate share of PV in Lighting services is 26.5%, Computing/internet services are 70.6%, Entertainment Services is 13.7%, Process heat Services is 0%, Cooking Services is 0%, Water pumping Services is 0%, Refrigeration services are 0%, and Ventilation services are 4.4%. The Total share of PV for energy services in Alagbaka Housing Estate is 6.7%. In Sunshine Housing Estate share of PV in Lighting services is 24.0%, Computing/internet services are 50%, Entertainment Services is 14.1%, Process heat Services is 0%, Cooking Services is 0%, Water pumping Services is 0%, Refrigeration services are 0%, and Ventilation services are 1.8%. The Total share of PV for energy services in Ijapo Housing Estate is 4.4%. The Overall share of PV in Lighting services is 27.2%, Computing/internet services are 59.6%, Entertainment Services is 16.3%, Process heat Services is 0%, Cooking Services is 0%, Water pumping Services is 0%, Refrigeration services are 0%, and Ventilation services are 6.9%. The overall share of PV for energy services is 7.33%, as shown in Table 17, which is lower than the proposed 18% target set by the renewable energy master plan in 2005.

CONCLUSION
The study concludes that the Status of Solar PV is working well although the current contribution of solar PV in energy demand split for the estates was still very low, with with a total share of 8.8%, 6.7% and 4.4% in Ijapo, Alagbaka and Sunshine Housing Estate despite various government interventions. Its usage level constituted an insignificant share of 27.9%, 57.3%, 18.3%, 0%, 0%, 0%, 0%, and 16.8% for the total lighting, computing/internet, entertainment, process heat, cooking, refrigeration, water pumping and ventilation services requirement respectively in Ijapo Housing Estate, 26.5%, 70.6%, 13.7%, 0%, 0%, 0%, 0%, and 16.5% for the total lighting, computing/internet, entertainment, process heat, cooking, refrigeration, water pumping and ventilation services requirement respectively in Alagbaka Housing Estate, and 24.0%, 50%, 14.1%, 0%, 0%, 0%, 0%, and 1.8% for the total lighting, computing/internet, entertainment, process heat, cooking, refrigeration, water pumping and ventilation services requirement respectively in Sunshine Housing Estate. PV utilization is currently limited to lighting services, computing/internet, entertainment, and ventilation services, whereas its high potentials for other services need to be explored. Also, food and vaccine preservation through refrigeration, ventilation and water pumping for provision of potable water and farm irrigation are yet to be fully harnessed.
Based on the findings from the study, the following are recommended 1. Government support for solar PV intervention in these Estates should be further encouraged. 2. Solar PV Usage for lighting, entertainment and computing services by the Estates is commendable and an increase in the intensity of usage essential. 3. Its usage for food and vaccine preservation through refrigeration; ventilation and water pumping for provision of potable water and farm irrigation should also be researched.
Funding: This research received no external funding.

Conflicts of Interest:
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